Metallic seat assembly for valves

Abstract

A valve seat assembly adapted to fit within an annular groove in a butterfly valve body. The seat assembly includes a pair of opposed metal seat rings generally L-shaped in cross section with overlapping outer legs seated and anchored in the bottom of the groove. The seat rings have flexible free inner end portions extending radially inwardly of the groove terminating at outwardly curled arcuate ends which contact the sealing surface of the valve disc and extend laterally of the groove in spaced relation to and over the adjacent valve body. A resilient soft seal is mounted between the metal seat rings and the sides of the metal seal rings are corrugated to grip and retain the soft seal in place. The end portions of each metal ring have a relatively long free length and are easily flexed laterally and radially outwardly of the valve body by contact with the outer periphery of the disc when the disc is moved to a closed position to maintain sealing contact with the disc without requiring a high operating torque.

What is claimed is: 
     
       1. A seat assembly adapted to fit within an inner annular groove in a valve body having a closure member with a peripheral sealing surface movable between open and closed positions, said seat assembly comprising an annular metal housing having spaced inner end portions extending radially inwardly beyond the groove and a base portion at the bottom of the groove, each end portion flaring laterally outwardly of the groove and terminating at an end spaced laterally of the groove; and a resilient soft seal mounted within the metal housing between the spaced inner end portions at a location to seal with said peripheral sealing surface in the closed position of the closure member, each end portion having a free unrestrained length and being flexible in both a radial direction and a lateral direction, each end portion adapted to contact in metal-to-metal sealing relation the adjacent peripheral sealing surface of the closure member when the closure member moves to a closed position and to be flexed radially and laterally outwardly by the closure member to maintain a tight sealing relation therewith.   
     
     
       2. A seat assembly as set forth in claim 1 wherein said outer metal housing comprises a pair of separate metal seat rings being generally L-shaped in cross section with outer legs of the seat rings being in lapped relation and forming the base portion of the metal housing at the bottom of the groove. 
     
     
       3. A seal assembly as set forth in claim 1 wherein said outer metal housing comprises a pair of separate seat rings having corrugated sides gripping the soft seal to retain the soft seal within the housing. 
     
     
       4. A seat assembly adapted to fit within an inner annular groove in a butterfly valve body having a valve member movable between open and closed positions, said seat assembly comprising a pair of metallic seat rings having legs seated in the bottom of the groove and having sides positioned adjacent opposed groove sides, each seat ring having a flexible inner end portion extending radially inwardly beyond the groove and terminating at an arcuate end extending laterally of the groove in spaced relation to and lapping the adjacent valve body; a resilient soft seal mounted between the metallic seat rings, and means to retain the soft seal between the seat rings, the soft seal and the arcuate ends of both seat rings being in simultaneous sealing contact relation with the valve member in the closed position thereof, said end portions being flexed both radially and laterally outwardly when initial contact is made with the valve member when moved to closed position and being in sealing contact with the valve member in the closed position thereof under all conditions of operation, said arcuate ends when exposed to fluid pressure in the closed position of the valve member being urged into tight sealing relation with the valve member.   
     
     
       5. A seat assembly as set forth in claim 4 wherein the sides of the seat rings are corrugated and grip the soft seal therebetween to define said means to retain the soft seal. 
     
     
       6. In a valve including a valve body, a valve chamber, a flow passage communicating with the valve chamber, an annular groove about the flow passage, and a valve member with a peripheral sealing surface mounted in said valve chamber for movement between open and closed positions relative to the flow passage; an improved seat assembly fitting within the annular groove, said seat assembly comprising a metal housing seated within the groove and having spaced inner end portions extending radially inwardly beyond the groove, and a resilient soft seal mounted within the metal housing between the spaced inner end portions at a location to seal against said peripheral sealing surface in the closed position of the valve member;   each end portion having a free unrestrained length and an end flaring laterally outwardly of the groove in lapping relation to the adjacent valve body, each end portion being flexible in both radial and lateral directions and contacting in metal-to-metal sealing relation the adjacent peripheral sealing surface of the valve member when the valve member moves to a closed position.   
     
     
       7. A butterfly valve comprising: a valve body having a flow passage therethrough, a butterfly disc mounted in the flow passage for movement between open and closed positions and having a peripheral sealing surface, an annular groove in the valve body about the flow passage;   an improved seat assembly seated within the annular groove, said seat assembly including a metal housing having spaced inner end portions extending radially inwardly beyond the groove and a resilient soft seal mounted within the metal housing between the spaced inner end portions at a location to seal with said peripheral sealing surface in the closed position of the disc, each end portion having an end extending laterally outwardly of the groove in lapping relation to the adjacent valve body, each end portion being flexible in both radial and lateral directions with the end thereof contacting in metal-to-metal sealing relation the peripheral sealing surface of the valve disc under all conditions of operation when the valve disc is in closed position.   
     
     
       8. In a butterfly valve including a valve body, a valve chamber, a flow passage communicating with the valve chamber, an annular groove about the flow passage, and a butterfly disc mounted in said valve chamber for movement between open and closed positions relative to the flow passage and having a tapered peripheral sealing surface; an improved seat assembly fitting within the annular groove, said seat assembly comprising a metal housing seated within the groove having spaced inner end portions extending radially inwardly beyond the groove, and a resilient soft seal mounted within the metal housing between the spaced inner end portions;   each end portion having a free unrestrained length and an arcuate curled end flaring laterally, each end portion being flexible in both radial and lateral directions and the arcuate end thereof contacting in metal-to-metal sealing relation the adjacent peripheral sealing surface of the valve disc when the disc moves to a closed position.   
     
     
       9. In a butterfly valve as set forth in claim 8 wherein the metal housing comprises a pair of separate metal seat rings being generally L-shaped in cross section with outer legs of the seat rings being snapped together in an overlapping relation and the soft seal being positioned between sides of the seat rings thereby to form the seat assembly. 
     
     
       10. In a butterfly valve as set forth in claim 9 wherein the leg of the outermost seat ring is of a width slightly greater than the width of the groove and is squeezed between the sides of the groove at the bottom corners thereof upon insertion of the seat assembly within the groove thereby bowing said legs radially inwardly and forming seals at the corners of the groove. 
     
     
       11. A butterfly valve comprising: a valve body having a flow passage therethrough, a butterfly disc mounted in the flow passage for movement between open and closed positions and having a peripheral sealing surface, an annular groove in the valve body about the flow passage difining a bottom and generally parallel spaced sides forming corners at the junctures with the bottom;   an improved seat assembly within the annular groove, said seat assembly comprising a pair of metallic seat rings generally L-shaped in cross section having legs seated in the bottom of the groove and having sides positioned adjacent opposed groove sides, each seat ring having a flexible inner end portion extending radially inwardly beyond the groove and terminating at an arcuate end extending laterally of the groove in spaced relation to and lapping the adjacent valve body;   a resilient soft seal mounted between the metallic seat rings, and means to retain the soft seal between the seat rings, the soft seal and the arcuate ends of both seat rings being in simultaneous sealing contact relation with the valve member in the closed position thereof, said end portions being flexed both radially and laterally outwardly when initial contact is made with the valve member when moved to closed position and being in sealing contact with the valve member in the closed position thereof under all conditions of operation, said arcuate ends when exposed to fluid pressure in the closed position of the valve member being urged into tight sealing relation with the adjacent sealing surface of the valve member.   
     
     
       12. A seat assembly as set forth in claim 11 wherein the sides of the seat rings are corrugated and grip the soft seal therebetween to define said means to retain the soft seal. 
     
     
       13. A butterfly valve as set forth in claim 11 wherein a separate metal spacer member is mounted between the seal rings radially outwardly of the soft seal and in contact with the soft seal, said spacer member upon destruction of the soft seal maintaining a spacing between the sides of the seat rings. 
     
     
       14. A butterfly valve as set forth in claim 11 wherein the leg of the outermost seat ring is of a width slightly greater than the width of the groove and is squeezed between the sides of the groove at the corners thereby bowing said leg radially inwardly and forming metal static seals at the corners of the groove. 
     
     
       15. A butterfly valve having a main body portion with a flow passage therethrough, a seat retainer of ring removably secured to the main body portion at a joint therebetween, a butterfly disc mounted in the flow passage for movement between open and closed positions, an annular groove about the flow passage at the joint between the retainer ring and main body portion, said groove defining a bottom and generally parallel spaced sides forming corners with the bottom; and an improved seat assembly in the groove; said seat assembly comprising a pair of metal seat rings being generally L-shaped in cross section with outer legs of the seat rings being in overlapped seated relation at the bottom of the groove and sides of the seat rings being positioned adjacent the spaced groove sides;   said retainer ring pressing said seat rings tightly against the sides of the groove, the sides of said seat rings having end portions engaging the butterfly disc in metal-to-metal sealing relation under all conditions of operation when the disc is in a closed position.   
     
     
       16. A butterfly valve as set forth in claim 15 wherein the leg of the outermost seat ring is of a width slightly greater than the width of the groove and is squeezed between the sides of the groove at the corners thereof to bow the outermost leg radially inwardly and form metal static seals at the corners of the groove 
     
     
       17. A butterfly valve as set forth in claim 16 wherein a portion of the groove bottom is tapered to urge the leg of the outermost seat ring inwardly upon positioning of the retainer ring in position. 
     
     
       18. In a butterfly valve including a valve body, a valve chamber, a flow passage communicating with the valve chamber, an annular groove about the flow passage, said groove defining a bottom and generally parallel spaced sides, and a butterfly disc mounted in said valve chamber for movement between open and closed positions relative to the flow passage and having a tapered peripheral sealing surface; an improved seat assembly anchored within the annular groove, said seat assembly comprising a pair of generally L-shaped metal seat rings having outer legs in an overlapped seated relation at the bottom of the groove and having integral sides positioned adjacent the spaced groove sides;   said seat rings each having an inner end portion, each of said inner end portions having a free unrestrained length extending radially inwardly beyond the groove and terminating at a laterally extending end, the ends of said inner end portions being spaced from each other and extending laterally in opposite directions, each inner end portion being flexible in both radial and lateral directions and the end thereof being adapted to contact in face-to-face sealing relation the adjacent peripheral sealing surface of the valve disc.   
     
     
       19. In a butterfly valve having a valve body with a flow passage therein and an internal annular groove in the body about the flow passage, and a butterfly valve disc mounted within the flow passage for pivotal movement between open and closed positions and having a peripheral sealing surface positioned adjacent the groove in said closed position; an improved seat assembly comprising: a pair of seat rings anchored in the groove defining an upstream seat ring and a downstream seat ring, each ring having a side positioned adjacent a different one of the opposed groove sides, each seat ring having a flexible inner end portion extending radially inwardly beyond the groove and terminating at an arcuate end extending laterally of the groove in spaced relation to and lapping the adjacent valve body, the inner end portions of the seat rings being spaced from one another and flaring laterally outwardly in opposite directions;   the arcuate ends of both seat rings being in simultaneous sealing contact relation with the peripheral sealing surface of the valve disc in the closed position thereof, said end portions being flexed both radially and laterally outwardly when initial contact is made with the valve disc upon movement to closed position and being in face-to-face sealing contact with the valve disc in the closed position thereof, the arcuate end of the upstream seat ring when exposed to fluid pressure from the flow passage in the closed position of the valve disc being urged by said fluid pressure into tight face-to-face sealing relation with the peripheral surface of the valve disc.   
     
     
       20. In a valve including a valve body, a valve chamber, a flow passage communicating with the valve chamber, an internal annular groove about the flow passage, and a valve member mounted in said valve chamber for movement between open and closed positions relative to the flow passage and having a tapered peripheral sealing surface; an improved seat assembly anchored within the annular groove and including a pair of seat rings having spaced inner end portions for providing a dual seal with said tapered peripheral sealing surface;   each of said inner end portions having a free unrestrained length outside the groove extending radially inwardly beyond the groove and terminating at a laterally extending end, one of the inner end portions having a substantially larger free unrestrained length than the other of said inner end portions, the ends of said inner end portions being spaced from each other and extending laterally in opposite directions, the inner end portions being flexible in both radial and lateral directions whereby the ends thereof are in simultaneous face-to-face sealing relation with the adjacent peripheral sealing surface of the valve member in the closed position thereof.